Hitler ordered the construction of the fortifications in 1942. Almost a million French workers were drafted to built it. The wall was frequently mentioned in Nazi propaganda, where its size and strength was usually exaggerated. The fortifications included colossal coastal guns, batteries, mortars, and artillery, and thousands of German troops were stationed in its defences. When the Allies eventually invaded the Normandy beaches in 1944, most of the defences were stormed within hours. Today, ruins of the wall exist in all of the nations where the wall was built, although many structures have fallen into the ocean or have been demolished over the years.

World War II in Europe began on 1 September 1939, with Nazi Germany's invasion of Poland. Two days later, on 3 September, Britain and France declared war on Germany.[1] Poland's geographical location prevented the Allies from intervening directly. Four weeks into the attack, the Germans had effortlessly occupied Poland.[1]

Less than a month after after this victory, Adolf Hitler issued a directive stating that Germany must be ready for an offensive through France and the Low Countries by November 1939.[1] However, the Oberkommando der Wehrmacht (German high command; OKW) was convinced that perparations would take at least until the following year. After furious arguments, Hitler reluctantly agreed to wait.[1] In May 1940, three massive German army groups overran France and the Low Countries in little more than six weeks.[1]

On 23 March 1942, Hitler issued Führer Directive No. 40, which called for the creation of an "Atlantic Wall". He ordered naval and submarine bases to be heavily defended. Fortifications remained concentrated around ports until late in 1943, when defences were increased in other areas.[2]Nazi propaganda claimed that the wall stretched from the cape of Norway down to the Spanish border.[3][4]

Organisation Todt, which had designed the Siegfried Line during the pre-war years along the Franco-German border, was the chief engineering group responsible for the design and construction of the wall's major gun emplacements and fortifications.[3][5] The Vichy regime imposed a compulsory labour system, drafting some 750,000 French workers to construct these permanent fortifications along the Dutch, Belgian, and French coasts facing the English Channel.[5]

Throughout most of 1942–43, the Atlantic Wall remained a relaxed front for the Axis troops manning it, with only two British attacks. Operation Chariot, launched near St Nazaire in March 1942, was an attempt to destroy German pumping machinery and installations.[6] The second attack was the Dieppe Raid, launched near the French port of Dieppe in August 1942 to test the German defences and provide combat experience for Canadian troops. The Germans suffered a decisive defeat at St Nazaire, but had little difficulty in repulsing the attack at Dieppe, where they inflicted heavy casualties.[7] After these attacks, Hitler gave Field Marshal Gerd von Rundstedt, the overall German Commander-in-Chief in the West, 15 further divisions to shore up the German positions.[7]

Early in 1944, with an Allied invasion of Nazi-occupied Europe becoming ever more likely, Field MarshalErwin Rommel was assigned to improve the wall's defences.[4][7] Believing the existing coastal fortifications to be entirely inadequate, he immediately began strengthening them.[7] Rommel's main concern was Allied air power. He had seen it first-hand when fighting the British and Americans in North Africa, and it had left a profound impression on him.[7] He feared that any German counterattack would be broken up by Allied aircraft long before it could make a difference.[7] Under his direction, hundreds of reinforced concretepillboxes were built on the beaches, or sometimes slightly inland, to house machine guns, antitank guns, and light and heavy artillery. Land mines and antitank obstacles were planted on the beaches, and underwater obstacles and naval mines were placed in waters just offshore.[8] The intent was to destroy the Allied landing craft before they could unload on the beaches.[8]

By the time of the Allied invasion, the Germans had laid almost six million mines in Northern France.[4] More gun emplacements and minefields extended inland along roads leading away from the beaches.[4] In likely landing spots for gliders and parachutists, the Germans emplaced slanted poles with sharpened tops, which the troops called Rommelspargel ("Rommel's Asparagus").[9] Low-lying river and estuarine areas were intentionally flooded.[7] Rommel believed that Germany would inevitably be defeated unless the invasion could be stopped on the beach, declaring "It is absolutely necessary that we push the British and Americans back from the beaches. Afterwards it will be too late; the first 24 hours of the invasion will be decisive."[8]

However, as the islands lacked strategic significance, the Allies bypassed them when they invaded Normandy. As a result, the German garrisons stationed on the islands did not surrender until 9 May 1945—one day after Victory in Europe Day. The garrison on Alderney did not surrender until 16 May. Because most of their garrisons surrendered peacefully, the Channel Islands are host to some of the best-preserved Atlantic Wall sites.[13]

Many major ports and positions were incorporated into the Atlantic Wall, receiving heavy fortifications. Hitler ordered all positions to fight to the end, and some of them remained in German hands until Germany's unconditional surrender. Several of the port fortresses were resupplied by submarines after being surrounded by Allied Forces. The defenders of these positions included foreign volunteers and SS troops.[14]

In France, immediately after the war, there was little interest in preserving the wall due to the negative memories associated with the Nazi occupation. In 2011, renewed efforts to preserve the wall were spearheaded by organisations in Germany, the Netherlands, and the United Kingdom. In France, many of the beach fortifications have toppled or are underwater, while the ones further inland are still mainly extant due to their location.[26] Although the defensive wall was never fully completed, many bunkers still exist near Scheveningen, Den Haag, Katwijk, and in Scandinavia.[27]